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Reilly NJ, Kokkin DL, Ward ML, Flores J, Ross SD, McCaslin LM, Stanton JF. Gas-Phase Optical Detection of 3-Ethynylcyclopentenyl: A Resonance-Stabilized C7H7 Radical with an Embedded 1-Vinylpropargyl Chromophore. J Am Chem Soc 2020; 142:10400-10411. [DOI: 10.1021/jacs.0c01579] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Neil J. Reilly
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Damian L. Kokkin
- Department of Chemistry, Marquette University, P.O. Box 1881 Milwaukee, Wisconsin 53201, United States
| | - Meredith L. Ward
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Jonathan Flores
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Sederra D. Ross
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston Massachusetts 02125, United States
| | - Laura M. McCaslin
- Institute of Chemistry and the Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 9190401, Israel
| | - John F. Stanton
- Quantum Theory Project, Departments of Chemistry and Physics, The University of Florida, Gainesville Florida 32611, United States
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2
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Huh CS. Jet-cooled spectroscopy of the m-ethylbenzyl radical in a corona-excited supersonic expansion. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 214:326-332. [PMID: 30798214 DOI: 10.1016/j.saa.2019.02.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/01/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
The vibronic structure of m-ethylbenzyl radical has been investigated in the gas phase for the first time in a corona-excited supersonic expansion (CESE). Assignment of the m-ethylbenzyl radical has been reported by comparing the spectra from m-xylene and m-ethyltoluene. The theoretical calculation, Density functional theory, of the D0 and D1 state structures of the m-ethylbenzyl radical was computed. Conclusive assignment of vibronic emission spectrum has been analyzed with an aid of Franck-Condon simulation in the D0-D1 transition.
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Affiliation(s)
- Chang Soon Huh
- Applied Chemistry Major, Division of Chemical Environmental Engineering, College of Engineering, Dong-Eui University, Pusan 614-714, Republic of Korea.
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3
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Spectroscopic identification of the p-ethylbenzyl radical in a corona-excited supersonic expansion. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.02.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Probing the Migration of Free Radicals in Solid and Liquid Media via Cr(VI) Reduction by High-Energy Electron Beam Irradiation. Sci Rep 2018; 8:15196. [PMID: 30315201 PMCID: PMC6185987 DOI: 10.1038/s41598-018-33676-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 04/04/2018] [Indexed: 11/16/2022] Open
Abstract
To probe the migration of free radicals (FRs), the reduction behaviours of hexavalent chromium (Cr(VI)) in water and ice by high-energy electron beam (HEEB) irradiation were investigated. Interestingly, the reductive efficiency (RE) of Cr(VI) in water was appreciably higher than that in ice. Thus, it was proposed that the migration ability of FRs in water is distinctly higher than that in ice, likely because the migration performance of FRs is closely related to the intermolecular distance of water molecules. Furthermore, the RE of Cr(VI) in ice decreased gradually with the distance from the irradiated area, indicating that FRs could migrate in ice and that the migration performance was closely related to the RE. Additionally, FRs (hydrated electrons (\documentclass[12pt]{minimal}
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\begin{document}$${{\rm{e}}}_{{\rm{aq}}}^{-}$$\end{document}eaq−) and hydrogen radicals (·H)) generated during the irradiation process played a key role in the reduction of Cr(VI). Hydroxyl radicals (·OH) and H2O2 were the dominant negative factors for the reduction because of their oxidizing effects, but these factors could be eliminated by the removal of ·OH. This work reveals the migration performance of FRs in different media for the first time. This result may be useful for basic and applied studies in fields of environmental science related to FRs.
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Steglich M, Bodi A, Maier JP, Hemberger P. Probing different spin states in xylyl radicals and ions. Phys Chem Chem Phys 2018; 20:7180-7189. [PMID: 29480313 DOI: 10.1039/c7cp08466h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Resonant one-color two-photon ionization spectroscopy and mass-selected threshold photoelectron spectroscopy were applied to study the electronic doublet states of the three xylyl (methyl-benzyl) radicals above 3.9 eV as well as the singlet and triplet states of the cations up to 10.5 eV. The experiments are complemented by quantum chemical calculations and Franck-Condon simulations to characterize the transitions and to identify the origin bands, allowing a precise determination of singlet-triplet splittings in the cations. Torsional motions of the methyl group notably affect the D0 → D3 transition of m-xylyl. All other investigated transitions either lead to electronic states with very low rotational barriers or suffer from spectral broadening in excess of methyl torsional energy levels. The methyl internal rotational potential is faithfully reproduced with the most basic ab initio methods, yet hyperconjugation could not be identified as a significant force shaping them. Time-dependent density functional theory describes the excited electronic states better than wave function theory approaches, notably EOM-CCSD.
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Reilly NJ, da Silva G, Wilcox CM, Ge Z, Kokkin DL, Troy TP, Nauta K, Kable SH, McCarthy MC, Schmidt TW. Interconversion of Methyltropyl and Xylyl Radicals: A Pathway Unavailable to the Benzyl–Tropyl Rearrangement. J Phys Chem A 2018; 122:1261-1269. [DOI: 10.1021/acs.jpca.7b11914] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Neil J. Reilly
- Department
of Chemistry, University of Massachusetts Boston, 100 Morrissey
Boulevard, Boston, Massachusetts 02125, United States
| | - Gabriel da Silva
- Department
of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Callan M. Wilcox
- School
of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Zijun Ge
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Damian L. Kokkin
- Department
of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin 53201-1881, United States
| | - Tyler P. Troy
- Advanced
Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Klaas Nauta
- School
of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Scott H. Kable
- School
of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Michael C. McCarthy
- Harvard−Smithsonian
Center for Astrophysics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Timothy W. Schmidt
- School
of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
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7
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Moon CJ, Ahn A, Min A, Seong YG, Kim JH, Choi MY. Conformationally resolved spectroscopy of jet-cooled methacetin. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.09.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Chae SY, Lim M, Lee SK. Spectroscopic evidence of α,α-dimethylbenzyl radicals in the gas phase. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.10.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Korn JA, Tabor DP, Sibert EL, Zwier TS. Conformation-specific spectroscopy of alkyl benzyl radicals: Effects of a radical center on the CH stretch infrared spectrum of an alkyl chain. J Chem Phys 2016; 145:124314. [DOI: 10.1063/1.4963227] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joseph A. Korn
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Daniel P. Tabor
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Edwin L. Sibert
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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Kidwell NM, Mehta-Hurt DN, Korn JA, Zwier TS. Infrared and Electronic Spectroscopy of the Jet-Cooled 5-Methyl-2-furanylmethyl Radical Derived from the Biofuel 2,5-Dimethylfuran. J Phys Chem A 2016; 120:6434-43. [PMID: 27456434 DOI: 10.1021/acs.jpca.6b05877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic and infrared spectra of the 5-methyl-2-furanylmethyl (MFM) radical have been characterized under jet-cooled conditions in the gas phase. This resonance-stabilized radical is formed by H atom loss from one of the methyl groups of 2,5-dimethylfuran (DMF), a promising second-generation biofuel. As a resonance-stabilized radical, it plays an important role in the flame chemistry of DMF. The D0-D1 transition was studied using two-color resonant two-photon ionization (2C-R2PI) spectroscopy. The electronic origin is in the middle of the visible spectrum (21934 cm(-1) = 455.9 nm) and is accompanied by Franck-Condon activity involving the hindered methyl rotor. The frequencies and intensities are fit to a one-dimensional methyl rotor potential, using the calculated form of the ground state potential. The methyl rotor reports sensitively on the local electronic environment and how it changes with electronic excitation, shifting from a preferred ground state orientation with one CH in-plane and anti to the furan oxygen, to an orientation in the excited state in which one CH group is axial to the plane of the furan ring. Ground and excited state alkyl CH stretch infrared spectra are recorded using resonant ion-dip infrared (RIDIR) spectroscopy, offering a complementary view of the methyl group and its response to electronic excitation. Dramatic changes in the CH stretch transitions with electronic state reflect the changing preference for the methyl group orientation.
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Affiliation(s)
- Nathanael M Kidwell
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907-2084, United States
| | - Deepali N Mehta-Hurt
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907-2084, United States
| | - Joseph A Korn
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907-2084, United States
| | - Timothy S Zwier
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907-2084, United States
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13
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Spectroscopic evidence of jet-cooled p-methyl-α-methylbenzyl radical. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.05.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Troy TP, Tayebjee MJ, Nauta K, Kable SH, Schmidt TW. Atmospheric oxidation intermediates: Laser spectroscopy of resonance-stabilized radicals from p-cymene. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2014.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Kidwell NM, Mehta-Hurt DN, Korn JA, Sibert EL, Zwier TS. Ground and excited state infrared spectroscopy of jet-cooled radicals: Exploring the photophysics of trihydronaphthyl and inden-2-ylmethyl. J Chem Phys 2014; 140:214302. [DOI: 10.1063/1.4879550] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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